Method and apparatus for forming foundation columns



April 18, 1933. Q L PQWELL 1,904,079

METHOD Am) APPARATUS FOR FORMING FOUNDATION COLUMNS Filed March 16. 19522 Shets-Sheeg l FIGJ. H62.

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BY W @I/[ r ATTORNEY5 April 18, 1933. C POWELL 1,904,079

METHOD AND APPARATUS FOR FORMING FOUNDATION COLUMNS Filed March 16. 19322 Sheets-Sheet 2 FIGS.

FIGB.

INVEN R- BY W M ATTORNEY;

Patented Apr. 18, 1933 UNITED STATES PAT NT OFFICE PANY, 01 NEW YORK, N.Y., A. CORPORATION OF DELAWARE METHOD ND APPARATUS non FORMINGronNnArIou COLUMNS This invention pertains to the making of foundationsand the like for buildings and other structures, particularlyfoundations of the concrete pier or column type which are sunk into theground by pneumatic caissons in order to reach suitable foo-tings j Aswill appear from the following description, the invention provides anumber of ad vantages over pneumatlc cassion methods heretofore used. YThe working chamber at the lower end of the caisson is of largerdiameter than the shaft that extends up to ground level. This means thatthe'only substantial frictional resistance encountered in sinking thecaisson is that between the chamber and the wall of the excavation. Theresistance is therefore held to a minimum, and is, furthermore,substantially constant, as distinguished from the usual practice, inwhich the caisson throughout its length is the full diameter of the holewhereby the frictional resistance increases with the depth of theexcavation.

With theworking chamber of larger diameter than the shaft, liquid suchas water or mud-laden fluid may be used to fill the annular space abovethe working chamber, thus serving not only to decrease the additionalload required for sinking but also to prevent caving of the walls of thehole above the working chamber.

The frictional resistance of the caisson is practically constant at alldepths; and the weight of the shaft is almost as great per foot oflength as its displacement. Consequently, if the method of lowering theair pressure temporarily, to drop the caisson, is used, friction shouldprevent uplift and therefore only a small amount of additional weight,if any, will be required.

The present invention permits raising and recovery of the workingchamber and shaft during the concreting operation, the raising usuallybeing accomplished by air pressure or by using air pressure to assisthoisting cables or jacks.

Further and other objects and advantages will be apparent from thespecification and claims, and from the accompanying draw- Applicationfiled March 16, 1932. Serial No. 599,073.

ings which illustrate what isnow considered the preferred embodiment ofthe invention."

Fig. 'l-shows the apparatus during thesinking ofahole.

Fig. 2 shows the apparatus afterthe hole has been sunk to rock, or otherfooting, and

concreting begun.

Fig. 3 shows the concreting operation under way after removal of theman-andmaterial lock, the caisson being partly raised.

Fig. 4 shows thec'ompletedcolumn or pier.

. Fig. 5 shows the concrete hopper on-the top of the shaft.-

Fig. 6 shows an enlarged view of themanand-material lock with theauxiliary shaftsealing partition in broken lines. f

Fig. 7 is an enlarged view of the sealing partition in operativeposition.

Fig. 8 is a viewon line88 of Fig. 7

Referring to the drawings, the working chamber 20 of the caisson'isprovided with an upwardly extending man-and-material shaft 22. To beginoperations the chamber is set in position on the ground surface'or onthe bed of a stream or other body of water, or on the bottom of a holewhich may have been dug by any known method.

In any event after the chamber has been set in position with suficientshafting to extend well above the starting surface, the hole is filledwith liquid such as water or mud-laden fluid to balance the normal fluidpressure at the bottom ofthe working chamber and to prevent the walls ofthe hole from'caving above the working chamber. A man-andcHAnLns L.POWELL, on NEW YORK; N. Y., ASSIGNOR To CAISSON CONTRACTING com- :1,

material lock 24; isattached to the top of the shaft and air pressure isadmitted to shaft and ejected from chamber 7 and shaft, men withdigging. tools are lowered through the lock down the'shaft into theworking chamber.

flooding chamber and shaft'with liquid to equalize the pressure in theworking chamber. The weightsand platform, if used, and

lock are then removed, the required section of shaft added, the lock,and, if necessary, the platform and weights replaced, and air pressureapplied to blow out the shaft and chamber' again. The men are thenreturned to work.

Another method of changing the shaft length, when frictional resistanceexceeds buoyancy, is to place an auxiliary partition in the upper end ofthe shaft belowthemen as they come up theshaft. Suflicient air pressureis then maintainedbelow that partition to prevent flooding of shaft andchamber while the shaft changes are being made above. In Figs. 6, 7, and8" one form of partition is shown. It comprises two half partitions 4Ohinged together by hinges 42. Ad jacent. the hinges each half partitionhas a downwardly projecting flange 44, and between the flanges, when thepartition is in operative position, is a sheet'of resilient packing 46to prevent leakage of air. Around the outer edge of the upper side ofthe partition is a ring 48 of resilient packing. Within the upper endofeach section of shaft 22 is a steel ring 50. To apply the partition,it is folded at the hinge, lowered below ring 50, and then raisedbychains 52 into its operative position (Fig. 7), and then air valve 54and hose 56 are attached, through which air is supplied to the shaft andchamber below the partition. After the lock has been opened preparatoryto its removal, the air pressure below the partitionserves to hold thepartition in operative position without the assistancefof chains 52.While, removing the lock and attaching the new shaft section, hose 56may be temporarily disconnected. Itis only necessary to have-thehoseconnected sufliciently to replace any air whichmay leak slowly pastpartition 40.

After the lock is replaced andthe pressure equalized, the partition maybe removed.

The hole is thus excavated down to rock or other footing 58 after whichthe footing is prepared for concrete. After inspection, the men go outthrough the lock and the pouring of concrete begins. The concrete 59 isintroduced through the concrete hopper 60 then rises.

(Fig. 6) and door 62 on the lower end of the hopper in the usual manner.When the concrete has reached a sutficient height, the caisson is madeslightly buoyant by removing enough of the weights 26 or, if thefrictional resistance has been sufficient to make the weights 26unnecessary, by slightly increasing the air pressure to press downwardlyagainstthe concrete and upwardly against thecaisson. The slightlybuoyant caisson This rising may be controlled either by addingorremovingenough of the weights 26 or by increasing or reducing the air pressureor by both. As the caisson is thus raised, more concrete is added untilthe caisson reaches a level where the'weight of concrete, above thebottom edge, of the working chamber, equals the external pressure there.When that level is reached, weights 26, platform 28, concrete hopper 60,

lock 24, and some of the shafting 22 are removed. Concrete hopper 6Ois'then connected directly to the top flange of the remaining shafting22 and, air being admitted through pipe 66 (Figs. 3 and 5), theconcreting and raising process is resumed.

. As the working chamber and shaft rise, the water or mud-laden fluid 68surrounding the shaft is displaced outof the top of the.

hole. The shaft is successivelyshortened untilthe concrete in theexcavation reaches the required height, whereupon'the remainder of theshaft, and the working chamber are hoisted out of the hole, leaving thefinished column as in Fig. 4.

The recovered work chamber and shaft may be re-used, as desired.

It is to be understood that the invention is not limited to the'specificembodiment herein illustrated and described, but may be used in otherways without departure from its spirit as defined by the followingclaims.

I claim:

1. A caisson for sinking a hole in the ground, comprising incombination, a working chamber of substantially the diameter of thehole, a shaft of lesser diameter extending from the top of said chamberand being free of the walls of the hole, and means for preventingentranceof extraneous material into said caisson. I

2. Apparatus for sinking a hole inthe ground, comprising in combination,a workin gchamber of substantially the diameter of the hole, a shaft oflesser diameter extending from the top of said chamber and being free ofthe walls of the hole, and an airlock on the top of said shaft,substantially as described.

3. Apparatus for sinking a hole in the ground, comprising incombination, a working chamber, a shaft extending upwardly from saidchamber, said'shaft comprising comparatively short sections, eachsection having an internal circumferential band therein, and acollapsible partition insertable through the top of said shaft to aposition below any one'of said bands and expansible thereunder and incontact therewith for providing a substantially airtight ance betweenthe caisson and walls of the hole.

5. In the method of digging a hole in the ground with a caisson, thesteps oflowering the caisson as the digging proceeds and graduallyincreasing the length thereof, maintaining substantially constantfrictional re sistance between the caisson and walls of the hole andwithdrawing the caisson after the hole is completed.

' 6. In the method of forming a concrete column in the ground with acaisson, the steps of lowering the caisson until a hole of the desireddepth is provided, depositing plastic concrete in the interior of thecaisson, and introducing fluid under pressure into said caisson abovesaid concrete whereby said caisson is forced upwardly from said hole.

7 In the method of digging a hole in the ground, the steps of providinga caisson having a working chamber at its lower end and a shaft of lessdiameter than the chamber and free of the walls of the hole extending upwardly from said chamber and excavating the ground below said caissonuntil the chamber reaches the desired depth and filling the caisson withplastic concrete.

8. In the method of digging a hole in the ground, the steps of providinga caisson having a working chamber at its lower end and a shaft of lessdiameter than the chamber and free of the walls of the hole extendingupwardly from said chamber, excavating the ground below said caissonuntil the chamber reaches the desired depth, introducing plasticconcrete into the hole through said caisson, and withdrawing the caissongradually as the introduction of concrete proceeds. v

9. In the method of digging a hole in the ground, the steps of providinga caisson having a working chamber at its lower end and a shaft of lessdiameter than the chamber and free of the walls of the hole extendingupwardly from said chamber, excavating the ground below said caissonuntil the chamber reaches the desired depth, introducing plasticconcrete into the hole through said caisson, introducing fluid underpressure into said caisson above the concrete whereby the caisson isforced upwardly from the hole.

10. In the method of digging a hole in the ground, the steps ofproviding a caisson having a working chamber at its lower end and ashaft of lessdiameter than the chamher and free of the walls of the holeextendlng upwardly from said chamber, excavating below the caissonwhereby the caisson sinks into the ground, and applying an increasingload to the roof of the working chamber as the caisson sinks lower intothe ground.

11. In the method of digging a hole in the ground, the steps ofproviding a caisson having a working chamber at its lower end and ashaft of less diameter than the chamber and free of the walls of thehole extending upwardly from said chamber, excavating below the caissonwhereby the caisson sinks into the ground, and preventing collapse ofthe. wall of the hole above said chamber by maintaining liquid in thehole above said chamber.

12. The method of sinking a caisson in the ground to form a hole, whichconsists in excavating the ground below said caisson, maintaining fluidpressure tending to lift said caisson, and applying a fluid load to 7said caisson within the hole tending to neutralize the pressure actingto lift the caisson.

13. The method of sinking a caisson in the ground to form a hole, whichconsists in excavating the ground below said caisson, maintaining fluidpressure within the caisson tending to lift said caisson, andmaintaining a liquid load exterior of the caisson and within the holetending to neutralize the'action of the fluid pressure and preventingcollapse of the wall of the hole.

In testimony whereof I hereto afiix my signature.

CHARLES L. POWELL.

